Heretofore it has been taught that pyrochlore structure electrocatalyst materials of the general formula: EQU A.sub.2 [B.sub.2-x B'.sub.x ]O.sub.7-y
wherein A is selected from any of the pyrochlore structure metal cations in a group consisting of: Pb, Bi and Tl, wherein B' is selected from any of the pyrochlore structure metal cations in a group consisting of Pb, Bi, Tl, and Sn; wherein B is a pyrochlore structure metal cation at least a major portion of which is selected from a group consisting of at least one of: Ru, Rh, Ir, and Os, wherein y is equal to or greater than zero and equal to or less than one; and wherein x is equal to or less than one and equal to or greater than zero, may be used in the evolution or reduction of oxygen in alkaline solutions. Efforts to explore still other uses for these novel electrocatalyst materials were undertaken when it was noted that they may have ability to change their oxide content or stoichiometry, as a function of potential in alkaline solutions. It was suggested that this behavior might be useful to initiate oxidative reactions of various oxidizable organic compounds.
While it may be argued that the prior art has suggested using pyrochlore electrocatalyst materials for the oxidation of organic substances (see German Application No. 2150039, filed Oct. 7, 1971; and U.K. Patent Specification No. 1,415,684, published Nov. 26, 1975), the electrocatalyst materials of this invention have obtained unique end products through an unusual "reaction selectivity", or "partial oxidation". To better understand what we mean by "reaction selectivity" and "partial oxidation" in terms of this invention, comparison will be made with well known oxygen producing electrocatalyst materials such as platinum. Platinum has been observed to oxidize certain organic compounds to completion and form only carbonates as a reaction end product. This is not a useful result in the context of this invention.
By comparison, the electrocatalyst materials of this invention will catalyze certain organic substances to useful end products such as: carboxylates, carboxylic acids, ketones, etc., in a "partial oxidative" process i.e., a reaction which goes to completion without fully oxidizing the organic reactants.
The new and unexpected reaction products are often observed to be the result of unique reaction pathways or cleavages which as a group of reactions have never before been achieved by electrocatalysis to the best of the inventors' knowledge. It is believed that these uniquely "selective" results are substantially due to the particular and unusual catalytic characteristics of these pyrochlores. The high level of catalytic activity attainable with these materials can be attributed to the high surface area with which they can be fabricated, as taught in the aforementioned U.S. Pat. No. 4,129,525.